It’s just because the click event opens the menu, but OSX hasn’t allowed the app to take focus, so it realises that it’s not the foreground app, and cancels the menu. It’s a bit obscure - is it really a problem for you?
No it’s not a big problem, i won’t bother you with this anymore.
OSX does allow popup menu’s on windows that don’t have focus.
I want to keep our Juce app as close to a native OSX app as possible, so the behaviour should be the same. The best bet is to actually not allow the poupmenu to be shown as it won’t work anyway.